Atistralian and Tasmanian Malacodermidae. 49 



Synchonnus, Wat., 111. Typ. Col., p. 59. 

 Stademts, Wat., /. c, p. 61. 

 Jchras, Wat., /. c, p. 61. 



This is tlie genus most numerously represented in Aus- 

 tralia and Tasmania of all the Malacoderjnes ; it has as 

 well a wide distribution in New Guinea and the Malay 

 Archipelago. In consequence of the great diversity which 

 exists in parts generally quite constant, it has been split 

 up into a number of genera, but I think few of these will 

 eventually stand. 



The most remarkable variation occurs in the rostrum, 

 in some species {rhipidius, nigripes, etc.) it is long, 

 rather thin and shining; these were regarded by Mr. 

 Waterhouse as belonging to a distinct genus — Porro- 

 stoma. In others (j'ujipcnnis, fallax, etc.) it is either 

 entirely absent, or very short (wider than long), these he 

 considered as belonging to Mctriorrhynchus. Were there 

 no intermediate forms undoubtedly two genera could be 

 maintained, but there are so many of these that it is 

 quite impossible to define a boundary between the two 

 sections. 



Great variation also occurs in the prothorax and anten- 

 nae. The former is usually divided into 7 distinct areolets, 

 but in a few species these are not very sharply defined. 

 Others have but 5 or 3 areolets (all of these have the 

 rostrum either very short or absent), and for these also 

 new genera were proposed. One section has the prothorax 

 3-areolate, and the sutural costa of the elytra trifurcate at 

 base ; for this section the genus Trichalns was proposed, 

 and is here regarded as distinct, but merely for the sake of 

 convenience. 



The antennae vary from being strongly flabellate in the 

 male to but slightly serrate in both sexes. The second 

 joint is usually very small and partially concealed. 



Zijcus australis, Boisd., and ochraceus, Dalm., probably 

 belong to this genus, but I think it best at present to 

 treat them as being of doubtful position.* 



The following species are unknown to me : — 



Clienhdus, Wat., femoirdis, Macl., and vittatiis, Blackb. 

 These are commented upon at length hereafter. 



* See list of doubtful species at end. 

 TEANS. ENT. SOC. LOND. 1909. — PART I. (mAY) E 



